Message #258433

[Abraxas]

NASA/ESA/K. Retherford/SWRI Artist's concept of a plume of water vapor thought to be ejected off Europa. The key reason why life is more likely to exist on Europa than most other places in the solar system is because of the tidal energy that Jupiter's powerful gravitational pull exerts on the tiny moon.

This tidal energy is what keeps the salty water on Europa a liquid and is why Christopher McKay, a senior scientist at the Space Science and Astrobiology Division at NASA Ames Research Center, ranks Europa as one of the top places to find alien life in our solar system.

During a live webcast hosted by The Kavli Foundation in January, McKay said the three most likely places to find ET are: Saturn's moon Enceladus, Mars, and Europa. The key feature all of these places have in common is evidence for present or past liquid water.

"Nothing grows or reproduces when the water activity falls below some pretty high value, actually," McKay said during the webcast. "Microorganisms need surprisingly wet conditions."

Equally important is the interaction between Europa's underground ocean and icy surface.

In 2013, the Hubble Space Telescope saw water vapor above the moon's south pole, which scientists suspect came from an erupting plume beneath the icy crust.

If water can escape the ocean, then it's likely that gases like carbon and oxygen can enter it. Carbon and oxygen are key elements for life in Earth's oceans, so why not in Europa's as well?

"When I think about the fluxes of oxygen to Europa's ocean, I wonder if Europa could have the kinds of vigorous biosphere that Earth has that supports larger forms of life," Vance told Business Insider. "And then the imagination can go wild thinking about fish and octopi and whatever else might live in an ocean that's 100 kilometers deep."
Looking to Earth for answers

The best place astrobiologists can look to for ideas of what kinds of life might be lurking underneath Europa's icy shell is right here on Earth — deep under the oceans.